diff options
Diffstat (limited to 'lib/stdlib/doc')
| -rw-r--r-- | lib/stdlib/doc/src/notes.xml | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/lib/stdlib/doc/src/notes.xml b/lib/stdlib/doc/src/notes.xml index ef12e525e3..605a9f224d 100644 --- a/lib/stdlib/doc/src/notes.xml +++ b/lib/stdlib/doc/src/notes.xml @@ -31,6 +31,247 @@ </header> <p>This document describes the changes made to the STDLIB application.</p> +<section><title>STDLIB 3.9</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p> Fix a bug in <c>string:lexemes/2</c>. </p> <p> The + bug was found when optimizing the handling of deep lists + of Unicode characters in the <c>string</c> module. </p> + <p> + Own Id: OTP-15649</p> + </item> + <item> + <p>A bug has been fixed in the <c>maps</c> implementation + that could cause a crash or memory usage to grow until + the machine ran out of memory. This could happen when + inserting a new key-value pair with a key <c>K1</c> + containing a binary <c>B1</c> into a map <c>M</c> having + a key <c>K2</c> with a binary <c>B2</c> if the following + conditions were met:</p> <list> <item><c>B1 =/= + B2</c></item> <item><c>size(B1) >= 4294967296</c></item> + <item><c>size(B2) >= 4294967296</c></item> + <item><c>size(M) >= 32</c></item> <item><c>(size(B1) rem + 4294967296) == (size(B2) rem 4294967296)</c></item> + <item>the first <c>(size(B1) rem 4294967296)</c> bytes + are the same both in <c>B1</c> and <c>B2</c></item> + <item>substituting <c>B1</c> in <c>K1</c> with <c>B2</c> + would create a term with the same value as + <c>K2</c></item> </list> <p>The root cause of the problem + is that the <c>maps</c> implementation only hashed the + first <c>(X rem 4294967296)</c> bytes of binaries so that + different binaries could get the same hash value + independently of the hash seed.</p> + <p> + Own Id: OTP-15707</p> + </item> + <item> + <p> Since the introduction of the stack trace variable, + the Erlang Pretty Printer has left out the exception + class <c>throw</c> even when the stack trace variable + cannot be left out, which is not correct Erlang code. The + fix is to always include the exception class + <c>throw</c>. </p> + <p> + Own Id: OTP-15751</p> + </item> + <item> + <p><c>record_info/2</c> is a pseudo-function that + requires literal arguments known at compile time. + Therefore, the following usage is illegal: <c>fun + record/info/2</c>. The compiler would crash when during + compilation of that kind of code. Corrected to issue a + compilation error.</p> + <p> + Own Id: OTP-15760 Aux Id: ERL-907 </p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p> A new <c>rand</c> module algorithm, <c>exro928ss</c> + (Xoroshiro928**), has been implemented. It has got a + really long period and good statistical quality for all + output bits, while still being only about 50% slower than + the default algorithm. </p><p> The same generator is also + used as a long period counter in a new <c>crypto</c> + plugin for the <c>rand</c> module, algorithm + <c>crypto_aes</c>. This plugin uses AES-256 to scramble + the counter which buries any detectable statistical + artifacts. Scrambling is done in chunks which are cached + to get good amortized speed (about half of the default + algorithm). </p> + <p> + Own Id: OTP-14461 Aux Id: PR-1857 </p> + </item> + <item> + <p> + Types related to server naming and starting have been + exported from <c>gen_statem</c>. These are: + <c>server_name/0</c>, <c>server_ref/0</c>, + <c>start_opt/0</c>, <c>start_ret/0</c> and + <c>enter_loop_opt/0</c>.</p> + <p> + Own Id: OTP-14724 Aux Id: PR-2056 </p> + </item> + <item> + <p> + The default algorithm for the <c>rand</c> module has been + changed to <c>exsss</c> (Xorshift116**) which is a + combination of the Xorshift116 (<c>exsp</c>) state update + and a new scrambler "StarStar" from the 2018 paper + "Scrambled Linear Pseudorandom Number Generators" by + David Blackman and Sebastiano Vigna. This combination + should not have the caveat of weak low bits that the + previous default algorithm(s) have had, with the cost of + about 10% lower speed. See GitHub pull request #1969.</p> + <p> + Own Id: OTP-14731 Aux Id: PR-1969 </p> + </item> + <item> + <p> + The generic state machine behaviour <c>gen_statem</c> has + gotten code cleanup and documentation improvements from + GitHub Pull Request #1855, even though the PR itself was + rejected.</p> + <p> + Own Id: OTP-14737 Aux Id: PR-1855 </p> + </item> + <item> + <p> + Update Unicode specification to version 11.0.</p> + <p> + Own Id: OTP-15111</p> + </item> + <item> + <p> + ETS option <c>write_concurrency</c> now also affects and + improves the scalability of <c>ordered_set</c> tables. + The implementation is based on a data structure called + contention adapting search tree, where the lock + granularity adapts to the actual amount of concurrency + exploited by the applications in runtime.</p> + <p> + Own Id: OTP-15128</p> + </item> + <item> + <p> + Optimized <c>maps:new/0</c> with trivial Erlang + implementation, making use of literal terms (the empty + map) not needing dynamic heap allocation.</p> + <p> + Own Id: OTP-15200 Aux Id: PR-1878 </p> + </item> + <item> + <p>The <c>gen_*</c> behaviours have been changed so that + if logging of the last N messages through + <c>sys:log/2,3</c> is active for the server, this log is + included in the terminate report.</p> <p>To accomplish + this the format of "System Events" as defined in the man + page for <c>sys</c> has been clarified and cleaned up, a + new function <c>sys:get_log/1</c> has been added, and + <c>sys:get_debug/3</c> has been deprecated. Due to these + changes, code that relies on the internal badly + documented format of "System Events", need to be + corrected.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-15381</p> + </item> + <item> + <p> + The <c>gen_statem</c> behaviour engine loop has been + optimized for better performance in particular when the + callback module returns some actions, that is better + performance for more realistic applications than the Echo + Benchmark.</p> + <p> + Own Id: OTP-15452</p> + </item> + <item> + <p> Do not allow function specifications for functions + residing in other modules. </p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-15563 Aux Id: ERL-845, OTP-15562 </p> + </item> + <item> + <p> + The <c>persistent_term</c> functions <c>put/2</c> and + <c>erase/1</c> are now yielding.</p> + <p> + Own Id: OTP-15615</p> + </item> + <item> + <p>Previously, all ETS tables used centralized counter + variables to keep track of the number of items stored and + the amount of memory consumed. These counters can cause + scalability problems (especially on big NUMA systems). + This change adds an implementation of a decentralized + counter and modifies the implementation of ETS so that + ETS tables of type <c>ordered_set</c> with + <c>write_concurrency</c> enabled use the decentralized + counter. Experiments indicate that this change + substantially improves the scalability of ETS + <c>ordered_set</c> tables with <c>write_concurrency</c> + enabled in scenarios with frequent <c>ets:insert/2</c> + and <c>ets:delete/2</c> calls.</p> + <p> + Own Id: OTP-15623 Aux Id: PR-2190 </p> + </item> + <item> + <p> Use <c>ssh</c> instead of <c>rsh</c> as the default + remote shell. </p> + <p> + Own Id: OTP-15633 Aux Id: PR-1787 </p> + </item> + <item> + <p>Added <c>beam_lib:strip/2</c> and friends, which + accept a list of chunks that should be preserved when + stripping.</p> + <p> + Own Id: OTP-15680 Aux Id: PR-2114 </p> + </item> + <item> + <p> Optimize printing of maps with <c>io_lib:write()</c>. + Also optimize pretty printing of strings (<c>~s</c> and + <c>~ts</c>) when limiting the output with the + <c>chars_limit</c> option. </p> + <p> + Own Id: OTP-15705</p> + </item> + <item> + <p> There are new compiler options <c>nowarn_removed</c> + and <c>{nowarn_removed,Items}</c> to suppress warnings + for functions and modules that have been removed from + OTP.</p> + <p> + Own Id: OTP-15749 Aux Id: ERL-904 </p> + </item> + <item> + <p> Let the Erlang Pretty Printer put atomic parts on the + same line. </p> + <p> + Own Id: OTP-15755</p> + </item> + <item> + <p> Add option <c>quote_singleton_atom_types</c> to the + Erlang Pretty Printer's functions. Setting the option to + <c>true</c> adds quotes to all singleton atom types. </p> + <p> + Own Id: OTP-15756</p> + </item> + </list> + </section> + +</section> + <section><title>STDLIB 3.8.2</title> <section><title>Fixed Bugs and Malfunctions</title> |